"There's no question that it can be very hard to tell how 'Irish' a product is," says John Ruddy, editor of retail trade magazine Checkout.

"You have products that contain ingredients which are produced or grown abroad but are cooked or assembled here.

"How Irish is an 'Irish' Christmas cake, made in a factory in Tallaght, which contains raisins from Chile and sugar from Malaysia?" he says.

But a high-profile campaign called 'Love Irish Food' has been attempting to set a popular benchmark for what constitutes a truly Irish food or drink brand.

The campaign, run by a group of Irish food and drink manufacturers, started 18 months ago to educate consumers about the positive benefits of buying Irish and now has nearly 80 participating brands.

The criterion for participating brands is that they are at least 80% made in the Republic of Ireland and use ingredients from here where available. It's understood that some 10%-15% of applications to join the scheme are rejected because they fail this criteria.

There are other buy-Irish labelling schemes too, such as the National Dairy Council mark for milk and cream products, Bord Bia's Quality Assurance label scheme, and the long-established Guaranteed Irish mark -- although this scheme only stipulates that 50% of the product is made in Ireland compared to 80% for Love Irish Food.

You can also look for the oval-shaped EC identification mark on meat and dairy products. The first two letters contains the abbreviation of the EU country where it was produced -- such as IE for Ireland -- followed by a number and EC.